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Short Summary
Main recommendation: Replace struts in pairs whenever they show signs of failure, and inspect them around 50,000 miles, using common hand tools and penetrating fluid to loosen the old unit. The video demonstrates the full removal and installation on a 2006 Mazda 3, noting the process is similar for most vehicles. The MacPherson strut, a shock absorber with a coil spring around it, acts as the upper control arm and is critical to suspension and driving safety.
Key Points
- Four signs struts need replacing: the car feels unsettled or bounces like a trampoline, the struts leak oil, they are physically bent or too rusted to be safe, or the ride is harsh and the car sits too low and bottoms out.
- Struts should always be replaced in pairs, not one at a time.
- Soak bolts and joints in penetrating fluid ahead of time (ideally a day before) so they loosen more easily.
- Before installing, compare the old and new strut for matching bolt holes and mount positions, since the new part can look damaged but may have the same factory indentation.
- Clean the strut-to-knuckle contact area with a wire brush (and optionally brake cleaner) to prevent debris from being trapped.
- Jacking up the suspension can straighten a seized sway bar end link stud so it slides out more easily.
Details Worth Noting
- Concrete instructions:
- Tools: pry bars, hammers, flathead screwdriver, ratchets and wrenches, torque wrench, breaker bar, penetrating fluid, Vise-Grips, metal wire brush, Loctite, and optionally an impact gun.
- Remove the brake line by turning the wheel for access, popping the clip out with a flathead screwdriver, then unhooking the line from the strut.
- Remove the knuckle pinch bolt (17 mm) with a breaker bar, then finish with a ratchet.
- Remove the sway bar end link nut (14 mm wrench plus a Torx in the center). If the stud is seized, jack up the suspension to straighten it, or clamp the stud with Vise-Grips (grip the metal piece, not the rubber) and turn the nut off.
- Protect the ABS wire by removing its clip before hammering. Hit the knuckle downward until the strut separates.
- Remove the three strut tower bolts with a breaker bar, using a wrench if weather stripping blocks access.
- Before installing, mark the old bolt positions on the strut tower with a marker to approximate the original camber and alignment.
- Angle the top of the new strut in first, then bring the bottom to the knuckle. Use the new bolts (they come with washers), apply Loctite to the threads, and hand-tighten all three.
- Align the strut's back tab between the knuckle gap, jack the knuckle up while pushing the strut in, and confirm full seating when the bolt hole is clear.
- Clean the knuckle bolt, add Loctite, and torque the knuckle bolt to 65 ft-lb.
- Snap the sway bar end link into place with the ABS bracket and torque to 40 ft-lb.
- Reconnect the brake line and tap the clip in lightly.
- Lower the vehicle, remove the jack, and torque the strut tower bolts to 25 ft-lb.
- Penetrating fluid can be applied a day in advance for better results.
- ChrisFix mentions you might consider replacing sway bar end links at the same time since they're cheap and already apart, though this is just a suggestion, not a firm recommendation.
- Some strut towers allow bolt position adjustment for camber, which the marking tip helps preserve.
Bottom Line
Struts are a relatively simple, pair-based DIY job with common tools, provided you soak the fasteners, note the old alignment, and torque everything to spec, with the result being noticeably better control and reduced bounce.
